964 clutch pedal 2" below brake pedal
12-01-2013, 08:02 PM
#1
Track Day
Thread Starter
964 clutch pedal 2" below brake pedal
Warning, long post!
So, for the last 2 years I've been working on my 89 C4 "cleanup" project. Engine is back in the car and runs great. Problem is, my clutch pedal doesn't come back up all the way. Furthermore, it must be pressed to the soundproofing to disengage. If I put the wooden floor plate back in the pedal won't go down far enough to disengage the clutch. So, without the floor plate, you can actually drive the car but the friction point is just off the floor!
I've got a new master and slave cylinder along with a new flexible hose for the clutch slave. The engine has a new clutch, pressure plate and TO bearing. As this is an 89, with a single model year clutch, I had to pay through the nose to get the right clutch assembly but I'm convinced it is correct. Slave cylinder is indeed in the clutch release fork cup, as viewed from the inspection hole behind the rubber cover, so that isn't the issue.
In my frustration, I took the entire pedal assembly out assuming I had a failed roll pin in the clutch pedal shaft. No such luck, the pin came out and was not stressed at all! I lubricated everything and put in the original clutch master and it is obvious, the clutch pedal return is limited by the clutch master. The master bottoms out before the clutch pedal gets to its full return position. Note that this is the same behavior I get with a brand new clutch master.
I took the pedal assembly to my mechanic and, after inspecting it he determined there was nothing wrong, that is except for the pedal not returning to its fully out position.
I played with the adjustment mechanism but, after some reading, this is just a tension adjustment and doesn't affect the pedal position.
I've bled the system, realizing that my problem clearly appears mechanical, and, as expected, it changed nothing. I have all new fluid in the lines, both master and slave, and there is no air in the line. I even took a pole and pressed the clutch pedal while viewing the slave and clutch fork and I get motion in the slave almost immediately when I press the clutch pedal.
What seems pertinent to me is that with the pedal assembly removed and a clutch master installed in it, the pedal doesn't return all the way, seemingly being limited by the clutch master. I can't believe I've bent something in the pedal assembly and, on close inspection, everything looks straight and undamaged.
So, I'm stumped. What am I missing? Any ideas are welcome and appreciated. I'd really like to get this resolved so I can get the car to the paint shop to complete my "cleanup".
TIA
Jon
So, for the last 2 years I've been working on my 89 C4 "cleanup" project. Engine is back in the car and runs great. Problem is, my clutch pedal doesn't come back up all the way. Furthermore, it must be pressed to the soundproofing to disengage. If I put the wooden floor plate back in the pedal won't go down far enough to disengage the clutch. So, without the floor plate, you can actually drive the car but the friction point is just off the floor!
I've got a new master and slave cylinder along with a new flexible hose for the clutch slave. The engine has a new clutch, pressure plate and TO bearing. As this is an 89, with a single model year clutch, I had to pay through the nose to get the right clutch assembly but I'm convinced it is correct. Slave cylinder is indeed in the clutch release fork cup, as viewed from the inspection hole behind the rubber cover, so that isn't the issue.
In my frustration, I took the entire pedal assembly out assuming I had a failed roll pin in the clutch pedal shaft. No such luck, the pin came out and was not stressed at all! I lubricated everything and put in the original clutch master and it is obvious, the clutch pedal return is limited by the clutch master. The master bottoms out before the clutch pedal gets to its full return position. Note that this is the same behavior I get with a brand new clutch master.
I took the pedal assembly to my mechanic and, after inspecting it he determined there was nothing wrong, that is except for the pedal not returning to its fully out position.
I played with the adjustment mechanism but, after some reading, this is just a tension adjustment and doesn't affect the pedal position.
I've bled the system, realizing that my problem clearly appears mechanical, and, as expected, it changed nothing. I have all new fluid in the lines, both master and slave, and there is no air in the line. I even took a pole and pressed the clutch pedal while viewing the slave and clutch fork and I get motion in the slave almost immediately when I press the clutch pedal.
What seems pertinent to me is that with the pedal assembly removed and a clutch master installed in it, the pedal doesn't return all the way, seemingly being limited by the clutch master. I can't believe I've bent something in the pedal assembly and, on close inspection, everything looks straight and undamaged.
So, I'm stumped. What am I missing? Any ideas are welcome and appreciated. I'd really like to get this resolved so I can get the car to the paint shop to complete my "cleanup".
TIA
Jon
12-02-2013, 04:26 AM
#2
Drifting
I think it's air, in 9,5 out of 10 cases it is when the clutch pedal is strange. Have you used a Hammer for the bleeding procedure? You have to, in order to run the hydropump correctly. I'd say, get a Hammer or a Workshop and you'll be fine.
Thomas
Thomas
12-02-2013, 11:09 PM
#3
Track Day
Thread Starter
Thomas,
I agree that getting a Hammer and bleeding the system is a good idea. My issue is purely mechanical I think as once you remove the pedal assembly, it is clear that the clutch pedal doesn't come back to its full upright position even without any hydraulics connected. The clutch pedal seems to be constricted by the throw of the clutch master cylinder. Using the new one versus the one in the original assembly produces the same problem.
While I think bleeding is good, it is not a solution to my problem.
I agree that getting a Hammer and bleeding the system is a good idea. My issue is purely mechanical I think as once you remove the pedal assembly, it is clear that the clutch pedal doesn't come back to its full upright position even without any hydraulics connected. The clutch pedal seems to be constricted by the throw of the clutch master cylinder. Using the new one versus the one in the original assembly produces the same problem.
While I think bleeding is good, it is not a solution to my problem.
12-03-2013, 12:19 AM
#4
Rennlist Member
You don't need a Hammer to bleed the clutch. You will want a Motiv Power Bleeder though.
Also just try pulling the pedal up to the top of its travel. What happens?
Also just try pulling the pedal up to the top of its travel. What happens?
12-03-2013, 10:21 AM
#5
Jon, I had a similar issue that was fixed when I bled the clutch. In my case the pedal would not return to normal about 5% of the time. I could pull it back with my toe. Once bled properly the problem went away. I have a Motiv Power Bleeder if you want to try it on your car. I also have the scantool that might work the same as the hammer? My car is a C2 so I haven't used that feature.
12-03-2013, 12:16 PM
#6
RL Community Team
Rennlist Member
Rennlist Member
I visited and looked at the pedal assembly the other week -- this particular issue isn't with the fluid or lack of bleeding. The master cylinder is limiting the pedal's upward travel.
With the entire pedal assembly removed from the car, the pedal is physically incapable of traveling all the way up to its normal resting position. There is a hard stop. The master cylinder's piston hits the C-clip and prevents this from happening. Pulling any harder on it would require tearing the master cylinder piston through the C-clip.
This happens with both the old and the new master cylinder. I'm of the opinion something is bent, but as mentioned earlier the entire assembly appears fairly intact, along with the pin he pulled out to inspect.
The new and old cylinders both have exactly the same throw on the piston rod and are physically identical, so the issue must be with the pedal assembly.
I'll be out there tonight, if pictures would help.
With the entire pedal assembly removed from the car, the pedal is physically incapable of traveling all the way up to its normal resting position. There is a hard stop. The master cylinder's piston hits the C-clip and prevents this from happening. Pulling any harder on it would require tearing the master cylinder piston through the C-clip.
This happens with both the old and the new master cylinder. I'm of the opinion something is bent, but as mentioned earlier the entire assembly appears fairly intact, along with the pin he pulled out to inspect.
The new and old cylinders both have exactly the same throw on the piston rod and are physically identical, so the issue must be with the pedal assembly.
I'll be out there tonight, if pictures would help.
12-03-2013, 12:22 PM
#7
Had the exact same problem and by the end was close to ripping my hair out.
I bled the system, replaced the roll pin, changed both master and slave...
There are bushing inside the pedal assembly that wear out and fail - they did on mine.
Rather than going through the cost of breaking it down and rebuilding I bought a 993 pedal assembly off a breakers yard.
I'd be pretty confident in betting this is the problem.
Swap yours with another pedal box you know works and see if this is the issue...
I bled the system, replaced the roll pin, changed both master and slave...
There are bushing inside the pedal assembly that wear out and fail - they did on mine.
Rather than going through the cost of breaking it down and rebuilding I bought a 993 pedal assembly off a breakers yard.
I'd be pretty confident in betting this is the problem.
Swap yours with another pedal box you know works and see if this is the issue...
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12-03-2013, 12:50 PM
#9
Track Day
Thread Starter
Black-Betty,
I have completely disassembled the pedal assembly and inspected all of the "bearings". They are plastic and showed no wear so I simply lubricated things and put it back together. As stated before, the roll pin was also removed and inspected. Nada, nothing wrong there.
Likely I'll be traveling out to LPMM's place and doing an R&R on his pedal assembly as I think the only way I'm going to figure this out is to put the two side by side and see what's different.
BTW: I did look for a replacement unit but, so far, none to be found. Sure I can find one from LA Dismantlers or Okla. Foreign but I want to be sure that is my problem before I throw in replacement parts.
Thanks to all who have replied. I'll post again when I figure this thing out.
I have completely disassembled the pedal assembly and inspected all of the "bearings". They are plastic and showed no wear so I simply lubricated things and put it back together. As stated before, the roll pin was also removed and inspected. Nada, nothing wrong there.
Likely I'll be traveling out to LPMM's place and doing an R&R on his pedal assembly as I think the only way I'm going to figure this out is to put the two side by side and see what's different.
BTW: I did look for a replacement unit but, so far, none to be found. Sure I can find one from LA Dismantlers or Okla. Foreign but I want to be sure that is my problem before I throw in replacement parts.
Thanks to all who have replied. I'll post again when I figure this thing out.
12-03-2013, 12:53 PM
#10
Professor of Pending Projects
Rennlist Member
Rennlist Member
Replacing the pin and bushing on the pedal assembly is easy... Here you go:
https://rennlist.com/forums/964-foru...-few-q-12.html
But, as others have said... You do not need a hammer... bleed the clutch (best time to get a motive bleeder)... Do the easy stuff first before you start replacing parts or thinking about a clutch replacement...
https://rennlist.com/forums/964-foru...-few-q-12.html
But, as others have said... You do not need a hammer... bleed the clutch (best time to get a motive bleeder)... Do the easy stuff first before you start replacing parts or thinking about a clutch replacement...
12-03-2013, 12:54 PM
#11
Professor of Pending Projects
Rennlist Member
Rennlist Member
Black-Betty,
I have completely disassembled the pedal assembly and inspected all of the "bearings". They are plastic and showed no wear so I simply lubricated things and put it back together. As stated before, the roll pin was also removed and inspected. Nada, nothing wrong there.
Likely I'll be traveling out to LPMM's place and doing an R&R on his pedal assembly as I think the only way I'm going to figure this out is to put the two side by side and see what's different.
BTW: I did look for a replacement unit but, so far, none to be found. Sure I can find one from LA Dismantlers or Okla. Foreign but I want to be sure that is my problem before I throw in replacement parts.
Thanks to all who have replied. I'll post again when I figure this thing out.
I have completely disassembled the pedal assembly and inspected all of the "bearings". They are plastic and showed no wear so I simply lubricated things and put it back together. As stated before, the roll pin was also removed and inspected. Nada, nothing wrong there.
Likely I'll be traveling out to LPMM's place and doing an R&R on his pedal assembly as I think the only way I'm going to figure this out is to put the two side by side and see what's different.
BTW: I did look for a replacement unit but, so far, none to be found. Sure I can find one from LA Dismantlers or Okla. Foreign but I want to be sure that is my problem before I throw in replacement parts.
Thanks to all who have replied. I'll post again when I figure this thing out.
12-03-2013, 05:19 PM
#13
Professor of Pending Projects
Rennlist Member
Rennlist Member
12-05-2013, 05:16 PM
#14
Jon, I had a similar issue that was fixed when I bled the clutch. In my case the pedal would not return to normal about 5% of the time. I could pull it back with my toe. Once bled properly the problem went away. I have a Motiv Power Bleeder if you want to try it on your car. I also have the scantool that might work the same as the hammer? My car is a C2 so I haven't used that feature.
Gonna check it out this weekend. I'lll search RL for the DIY thread for bleeding the clutch.
I'll either invest in the Motiv Power Bleeder or see if some buddies have one to borrow.
Thanks!
12-07-2013, 03:13 PM
#15
Track Day
Thread Starter
mystery solved?
So, I took a pedal assembly from a friend's 964 so I had something to compare to mine. I pulled off the clutch pedal from both assemblies and compared them side by side. Note that the part numbers stamped on both clutch pedals is the same and, other than some spiffy pedal pads on my friend's, they should be identical.
I put a punch through the roll pin hole at the end of each of the clutch pedal shafts and placed them side by side. Man, are these two different! I now know why my pedal is so low, something is bent. It is really not obvious what is bent and the weld on the end of the shaft is not broken, but you can clearly see the 2+" of pedal difference from the angle of the roll pin hole to the top of the clutch pedal.
Looks like I'm shopping for a new clutch pedal as I have no idea how to correct this.
Check out the pics. I'm open to suggestions and I honestly didn't know how strong my left leg muscles must be! ;-)
I put a punch through the roll pin hole at the end of each of the clutch pedal shafts and placed them side by side. Man, are these two different! I now know why my pedal is so low, something is bent. It is really not obvious what is bent and the weld on the end of the shaft is not broken, but you can clearly see the 2+" of pedal difference from the angle of the roll pin hole to the top of the clutch pedal.
Looks like I'm shopping for a new clutch pedal as I have no idea how to correct this.
Check out the pics. I'm open to suggestions and I honestly didn't know how strong my left leg muscles must be! ;-)